This invention relates to a filtration apparatus, particularly but not exclusively a centrifugal filter, which is a term sometimes used for a fluid powered centrifugal separator, including a self-driven fluid powered centrifugal separator.
Fluid powered centrifugal separators are well-known for separating fluids of different densities or for separating particulate matter from liquids and have long been used in lubrication systems for engines, particularly diesel powered vehicle engines (automobiles and ships), as well as in other industrial separation processes. The principle of operation of such a separator is that a housing contains a rotor which is supported therein to spin at high speed about a substantially vertical axis. Fluid is supplied at elevated pressure along the axis of rotation, and passes through apertures in a central tube or axial cavity into the chamber of the rotor. Subsequently it is ejected from tangentially directed nozzles in the base of the rotor into the housing from which it drains to a sump. In self-powered separators the drive fluid for the rotor is the contaminated fluid which is to be cleaned. As this fluid passes through the rotor, denser contaminant materials or particles are separated therefrom centrifugally and are retained in the rotor, typically as a cake adhering to the interior surface of the rotor.
The rotor itself is typically formed in two parts as an upper bell shaped cover (referred to herein as a main housing body) and a lower base. In older arrangements, for example as disclosed in GB 2283694A, these were connected together by crimping. In more recent commercial versions of centrifugal separators, the cover is typically threadedly connected to the base and can therefore be unscrewed and screwed on again in servicing operations. In this respect, contaminant debris deposited in the interior of the rotor chamber, most of it adhering to the interior wall, but some not well adhered or lying free within the chamber, needs to be periodically removed. This may be done, for example, once or twice a year during vehicle servicing in the case of centrifugal separators in automotive vehicles, or may be done much more frequently in other industrial uses of centrifugal separators of this self-driven type. An example of this style of design is disclosed in applicant's own earlier GB 2465374A. An alternative design where the cover is connected to the base by means of a quick release clamp is disclosed in the applicant's own earlier GB 2478578A.
In some engine designs, it is now desirable that the cover, namely the main housing body, remains in place, while the base is the part which is removable during servicing. An object of the present invention is to improve the design of centrifugal separators for such purpose.